One-pot hydrothermal synthesis of a double Z-scheme g-C3N4/AgI/β-AgVO3 ternary nanocomposite for efficient degradation of organic pollutants and DPC-Cr(VI) complex under visible-light irradiation.

The Z-scheme photocatalytic system provides a promising way to achieve significant photodegradation efficiency. The work embodied here describes the synthesis of highly efficient double Z-scheme g-C3N4/AgI/β-AgVO3 (g-CNAB) ternary nanocomposite using a one-pot hydrothermal route. The optical properties, phase structure, and morphology of the synthesized samples were investigated using UV-visible diffuse-reflectance spectroscopy (UV-Vis DRS), X-ray diffraction, and scanning electron microscopy, respectively. The transmission electron microscopy investigation revealed that synthesized composite material represents close interfacial interactions. X-ray photoelectron spectroscopy analysis confirms the presence of all the elements in the synthesized ternary nanocomposite materials. The photocatalytic performance of as-prepared photocatalysts has been systematically investigated using the photodegradation of a variety of pollutants, including Rhodamine B, Ciprofloxacin, and 1,5-diphenylcarbazide-Cr(VI) [DPC-Cr(VI)] complex under visible-light irradiation. Among all synthesized materials, such as g-C3N4, AgI, β-AgVO3, and ternary nanocomposites with varying loading of β-AgVO3 [g-CNAB(0.5, 1.0, 1.5, 2.0)], the photocatalyst g-CNAB(1.5) nanocomposite achieved a remarkably high photocatalytic efficiency. The quenching impact of several scavengers revealed that reactive species such as superoxide anion radical (O2·-) and hydroxyl radical (·OH) are significant in the degradation of various contaminants. Based on the characterization and application, a plausible photocatalytic mechanism has been sketched out to determine the reaction pathways involved in the degradation of pollutants present in the aqueous medium.